fix "env use python" to use Python in PATH

[radoering]

This should use the Python, which is in the PATH, not the latest Python.

Pull Request Check List

Resolves: #10186

• Added tests for changed code.
• Updated documentation for changed code.

Summary by Sourcery

Fix the env use python command to select the Python executable specified in the user's PATH.

Bug Fixes:

• Use the Python executable found in the user's PATH when running env use python instead of the latest Python version available.

Tests:

• Add tests to verify that the correct Python executable is selected when using env use python.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request modifies the way Poetry locates Python executables. It now uses shutil.which to search for Python in the system's PATH when the env use python command is executed. This ensures that the Python executable in the PATH is used, rather than assuming the latest installed version. The pull request also includes new tests to verify the functionality of the changes.

Sequence diagram for locating Python executable

sequenceDiagram
  participant User
  participant Poetry
  participant ShutilWhichPythonProvider
  participant findpython

  User->>Poetry: env use python
  Poetry->>ShutilWhichPythonProvider: find_python_by_name("python")
  ShutilWhichPythonProvider->>shutil: which("python")
  alt Python found in PATH
    shutil-->>ShutilWhichPythonProvider: Path to python
    ShutilWhichPythonProvider->>findpython: PythonVersion(executable=Path(path))
    findpython-->>ShutilWhichPythonProvider: PythonVersion object
    ShutilWhichPythonProvider-->>Poetry: PythonVersion object
    Poetry->>Poetry: Use PythonVersion object to create Python environment
  else Python not found in PATH
    shutil-->>ShutilWhichPythonProvider: None
    ShutilWhichPythonProvider-->>Poetry: None
    Poetry->>findpython: find(python_name)
  end

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File-Level Changes

Change	Details	Files
Modified Python.get_by_name to use shutil.which to find Python executables in the system's PATH.	Replaced direct path existence checks and from_executable calls with ShutilWhichPythonProvider.find_python_by_name to locate Python. Removed the from_executable method from the Python class.	src/poetry/utils/env/python/manager.py
Implemented ShutilWhichPythonProvider to find Python executables using shutil.which.	Created ShutilWhichPythonProvider with find_pythons and find_python_by_name methods. The find_pythons method now returns a list containing the Python executable found using shutil.which('python'). The find_python_by_name method uses shutil.which to find a Python executable by a given name.	src/poetry/utils/env/python/providers.py tests/utils/env/python/test_python_providers.py
Added tests for Python.get_by_name and ShutilWhichPythonProvider.	Added tests to verify that Python.get_by_name correctly identifies Python versions based on name. Added tests to verify that ShutilWhichPythonProvider correctly finds Python executables in the PATH.	tests/utils/env/python/test_manager.py tests/utils/env/python/test_python_providers.py

Possibly linked issues

• Poetry 2.1.0 regression: poetry env use python uses the max python not the path python #10186: The PR fixes the "env use python" command to use the Python executable found in the PATH. This addresses part of the installation complexity raised in the issue.
• Poetry 2.1.0 regression: poetry env use python uses the max python not the path python #10186: PR fixes Python selection, indirectly addressing the activation issue by ensuring correct Python version is used.
• Poetry 2.1.0 regression: poetry env use python uses the max python not the path python #10186: The PR fixes a bug where poetry env use python uses the latest Python, not the one in PATH. The issue reports that .venv_2 is not being used when specified.

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[sourcery-ai]

Hey @radoering - I've reviewed your changes - here's some feedback:

Overall Comments:

• Consider adding a test case where python_name in get_by_name is an absolute path to a python executable.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟡 Testing: 1 issue found
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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[abn]

Not a blocker for this, but I am definitely curious if the reason why findpython.find(python_name) does not work as expected here has to do with how the action sets up the Python installation.